1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *	- Redistributions of source code must retain the above
15  *	  copyright notice, this list of conditions and the following
16  *	  disclaimer.
17  *
18  *	- Redistributions in binary form must reproduce the above
19  *	  copyright notice, this list of conditions and the following
20  *	  disclaimer in the documentation and/or other materials
21  *	  provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 #include <linux/kernel.h>
33 #include <linux/slab.h>
34 #include <linux/mm.h>
35 #include <linux/scatterlist.h>
36 #include <linux/kfifo.h>
37 #include <scsi/scsi_cmnd.h>
38 #include <scsi/scsi_host.h>
39 
40 #include "iscsi_iser.h"
41 
42 /* Constant PDU lengths calculations */
43 #define ISER_TOTAL_HEADERS_LEN  (sizeof (struct iser_hdr) + \
44 				 sizeof (struct iscsi_hdr))
45 
46 /* iser_dto_add_regd_buff - increments the reference count for *
47  * the registered buffer & adds it to the DTO object           */
48 static void iser_dto_add_regd_buff(struct iser_dto *dto,
49 				   struct iser_regd_buf *regd_buf,
50 				   unsigned long use_offset,
51 				   unsigned long use_size)
52 {
53 	int add_idx;
54 
55 	atomic_inc(&regd_buf->ref_count);
56 
57 	add_idx = dto->regd_vector_len;
58 	dto->regd[add_idx] = regd_buf;
59 	dto->used_sz[add_idx] = use_size;
60 	dto->offset[add_idx] = use_offset;
61 
62 	dto->regd_vector_len++;
63 }
64 
65 /* Register user buffer memory and initialize passive rdma
66  *  dto descriptor. Total data size is stored in
67  *  iser_task->data[ISER_DIR_IN].data_len
68  */
69 static int iser_prepare_read_cmd(struct iscsi_task *task,
70 				 unsigned int edtl)
71 
72 {
73 	struct iscsi_iser_task *iser_task = task->dd_data;
74 	struct iser_regd_buf *regd_buf;
75 	int err;
76 	struct iser_hdr *hdr = &iser_task->desc.iser_header;
77 	struct iser_data_buf *buf_in = &iser_task->data[ISER_DIR_IN];
78 
79 	err = iser_dma_map_task_data(iser_task,
80 				     buf_in,
81 				     ISER_DIR_IN,
82 				     DMA_FROM_DEVICE);
83 	if (err)
84 		return err;
85 
86 	if (edtl > iser_task->data[ISER_DIR_IN].data_len) {
87 		iser_err("Total data length: %ld, less than EDTL: "
88 			 "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
89 			 iser_task->data[ISER_DIR_IN].data_len, edtl,
90 			 task->itt, iser_task->iser_conn);
91 		return -EINVAL;
92 	}
93 
94 	err = iser_reg_rdma_mem(iser_task,ISER_DIR_IN);
95 	if (err) {
96 		iser_err("Failed to set up Data-IN RDMA\n");
97 		return err;
98 	}
99 	regd_buf = &iser_task->rdma_regd[ISER_DIR_IN];
100 
101 	hdr->flags    |= ISER_RSV;
102 	hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
103 	hdr->read_va   = cpu_to_be64(regd_buf->reg.va);
104 
105 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
106 		 task->itt, regd_buf->reg.rkey,
107 		 (unsigned long long)regd_buf->reg.va);
108 
109 	return 0;
110 }
111 
112 /* Register user buffer memory and initialize passive rdma
113  *  dto descriptor. Total data size is stored in
114  *  task->data[ISER_DIR_OUT].data_len
115  */
116 static int
117 iser_prepare_write_cmd(struct iscsi_task *task,
118 		       unsigned int imm_sz,
119 		       unsigned int unsol_sz,
120 		       unsigned int edtl)
121 {
122 	struct iscsi_iser_task *iser_task = task->dd_data;
123 	struct iser_regd_buf *regd_buf;
124 	int err;
125 	struct iser_dto *send_dto = &iser_task->desc.dto;
126 	struct iser_hdr *hdr = &iser_task->desc.iser_header;
127 	struct iser_data_buf *buf_out = &iser_task->data[ISER_DIR_OUT];
128 
129 	err = iser_dma_map_task_data(iser_task,
130 				     buf_out,
131 				     ISER_DIR_OUT,
132 				     DMA_TO_DEVICE);
133 	if (err)
134 		return err;
135 
136 	if (edtl > iser_task->data[ISER_DIR_OUT].data_len) {
137 		iser_err("Total data length: %ld, less than EDTL: %d, "
138 			 "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
139 			 iser_task->data[ISER_DIR_OUT].data_len,
140 			 edtl, task->itt, task->conn);
141 		return -EINVAL;
142 	}
143 
144 	err = iser_reg_rdma_mem(iser_task,ISER_DIR_OUT);
145 	if (err != 0) {
146 		iser_err("Failed to register write cmd RDMA mem\n");
147 		return err;
148 	}
149 
150 	regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
151 
152 	if (unsol_sz < edtl) {
153 		hdr->flags     |= ISER_WSV;
154 		hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
155 		hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);
156 
157 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
158 			 "VA:%#llX + unsol:%d\n",
159 			 task->itt, regd_buf->reg.rkey,
160 			 (unsigned long long)regd_buf->reg.va, unsol_sz);
161 	}
162 
163 	if (imm_sz > 0) {
164 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
165 			 task->itt, imm_sz);
166 		iser_dto_add_regd_buff(send_dto,
167 				       regd_buf,
168 				       0,
169 				       imm_sz);
170 	}
171 
172 	return 0;
173 }
174 
175 /**
176  * iser_post_receive_control - allocates, initializes and posts receive DTO.
177  */
178 static int iser_post_receive_control(struct iscsi_conn *conn)
179 {
180 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
181 	struct iser_desc     *rx_desc;
182 	struct iser_regd_buf *regd_hdr;
183 	struct iser_regd_buf *regd_data;
184 	struct iser_dto      *recv_dto = NULL;
185 	struct iser_device  *device = iser_conn->ib_conn->device;
186 	int rx_data_size, err = 0;
187 
188 	rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
189 	if (rx_desc == NULL) {
190 		iser_err("Failed to alloc desc for post recv\n");
191 		return -ENOMEM;
192 	}
193 	rx_desc->type = ISCSI_RX;
194 
195 	/* for the login sequence we must support rx of upto 8K; login is done
196 	 * after conn create/bind (connect) and conn stop/bind (reconnect),
197 	 * what's common for both schemes is that the connection is not started
198 	 */
199 	if (conn->c_stage != ISCSI_CONN_STARTED)
200 		rx_data_size = ISCSI_DEF_MAX_RECV_SEG_LEN;
201 	else /* FIXME till user space sets conn->max_recv_dlength correctly */
202 		rx_data_size = 128;
203 
204 	rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
205 	if (rx_desc->data == NULL) {
206 		iser_err("Failed to alloc data buf for post recv\n");
207 		err = -ENOMEM;
208 		goto post_rx_kmalloc_failure;
209 	}
210 
211 	recv_dto = &rx_desc->dto;
212 	recv_dto->ib_conn = iser_conn->ib_conn;
213 	recv_dto->regd_vector_len = 0;
214 
215 	regd_hdr = &rx_desc->hdr_regd_buf;
216 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
217 	regd_hdr->device  = device;
218 	regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
219 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
220 
221 	iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
222 
223 	iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
224 
225 	regd_data = &rx_desc->data_regd_buf;
226 	memset(regd_data, 0, sizeof(struct iser_regd_buf));
227 	regd_data->device  = device;
228 	regd_data->virt_addr  = rx_desc->data;
229 	regd_data->data_size  = rx_data_size;
230 
231 	iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
232 
233 	iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
234 
235 	err = iser_post_recv(rx_desc);
236 	if (!err)
237 		return 0;
238 
239 	/* iser_post_recv failed */
240 	iser_dto_buffs_release(recv_dto);
241 	kfree(rx_desc->data);
242 post_rx_kmalloc_failure:
243 	kmem_cache_free(ig.desc_cache, rx_desc);
244 	return err;
245 }
246 
247 /* creates a new tx descriptor and adds header regd buffer */
248 static void iser_create_send_desc(struct iscsi_iser_conn *iser_conn,
249 				  struct iser_desc       *tx_desc)
250 {
251 	struct iser_regd_buf *regd_hdr = &tx_desc->hdr_regd_buf;
252 	struct iser_dto      *send_dto = &tx_desc->dto;
253 
254 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
255 	regd_hdr->device  = iser_conn->ib_conn->device;
256 	regd_hdr->virt_addr  = tx_desc; /* == &tx_desc->iser_header */
257 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
258 
259 	send_dto->ib_conn         = iser_conn->ib_conn;
260 	send_dto->notify_enable   = 1;
261 	send_dto->regd_vector_len = 0;
262 
263 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
264 	tx_desc->iser_header.flags = ISER_VER;
265 
266 	iser_dto_add_regd_buff(send_dto, regd_hdr, 0, 0);
267 }
268 
269 /**
270  *  iser_conn_set_full_featured_mode - (iSER API)
271  */
272 int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
273 {
274 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
275 
276 	int i;
277 	/* no need to keep it in a var, we are after login so if this should
278 	 * be negotiated, by now the result should be available here */
279 	int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;
280 
281 	iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);
282 
283 	/* Check that there is no posted recv or send buffers left - */
284 	/* they must be consumed during the login phase */
285 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
286 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
287 
288 	/* Initial post receive buffers */
289 	for (i = 0; i < initial_post_recv_bufs_num; i++) {
290 		if (iser_post_receive_control(conn) != 0) {
291 			iser_err("Failed to post recv bufs at:%d conn:0x%p\n",
292 				 i, conn);
293 			return -ENOMEM;
294 		}
295 	}
296 	iser_dbg("Posted %d post recv bufs, conn:0x%p\n", i, conn);
297 	return 0;
298 }
299 
300 static int
301 iser_check_xmit(struct iscsi_conn *conn, void *task)
302 {
303 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
304 
305 	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
306 	    ISER_QP_MAX_REQ_DTOS) {
307 		iser_dbg("%ld can't xmit task %p\n",jiffies,task);
308 		return -ENOBUFS;
309 	}
310 	return 0;
311 }
312 
313 
314 /**
315  * iser_send_command - send command PDU
316  */
317 int iser_send_command(struct iscsi_conn *conn,
318 		      struct iscsi_task *task)
319 {
320 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
321 	struct iscsi_iser_task *iser_task = task->dd_data;
322 	struct iser_dto *send_dto = NULL;
323 	unsigned long edtl;
324 	int err = 0;
325 	struct iser_data_buf *data_buf;
326 
327 	struct iscsi_cmd *hdr =  task->hdr;
328 	struct scsi_cmnd *sc  =  task->sc;
329 
330 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
331 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
332 		return -EPERM;
333 	}
334 	if (iser_check_xmit(conn, task))
335 		return -ENOBUFS;
336 
337 	edtl = ntohl(hdr->data_length);
338 
339 	/* build the tx desc regd header and add it to the tx desc dto */
340 	iser_task->desc.type = ISCSI_TX_SCSI_COMMAND;
341 	send_dto = &iser_task->desc.dto;
342 	send_dto->task = iser_task;
343 	iser_create_send_desc(iser_conn, &iser_task->desc);
344 
345 	if (hdr->flags & ISCSI_FLAG_CMD_READ)
346 		data_buf = &iser_task->data[ISER_DIR_IN];
347 	else
348 		data_buf = &iser_task->data[ISER_DIR_OUT];
349 
350 	if (scsi_sg_count(sc)) { /* using a scatter list */
351 		data_buf->buf  = scsi_sglist(sc);
352 		data_buf->size = scsi_sg_count(sc);
353 	}
354 
355 	data_buf->data_len = scsi_bufflen(sc);
356 
357 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
358 		err = iser_prepare_read_cmd(task, edtl);
359 		if (err)
360 			goto send_command_error;
361 	}
362 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
363 		err = iser_prepare_write_cmd(task,
364 					     task->imm_count,
365 				             task->imm_count +
366 					     task->unsol_count,
367 					     edtl);
368 		if (err)
369 			goto send_command_error;
370 	}
371 
372 	iser_reg_single(iser_conn->ib_conn->device,
373 			send_dto->regd[0], DMA_TO_DEVICE);
374 
375 	if (iser_post_receive_control(conn) != 0) {
376 		iser_err("post_recv failed!\n");
377 		err = -ENOMEM;
378 		goto send_command_error;
379 	}
380 
381 	iser_task->status = ISER_TASK_STATUS_STARTED;
382 
383 	err = iser_post_send(&iser_task->desc);
384 	if (!err)
385 		return 0;
386 
387 send_command_error:
388 	iser_dto_buffs_release(send_dto);
389 	iser_err("conn %p failed task->itt %d err %d\n",conn, task->itt, err);
390 	return err;
391 }
392 
393 /**
394  * iser_send_data_out - send data out PDU
395  */
396 int iser_send_data_out(struct iscsi_conn *conn,
397 		       struct iscsi_task *task,
398 		       struct iscsi_data *hdr)
399 {
400 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
401 	struct iscsi_iser_task *iser_task = task->dd_data;
402 	struct iser_desc *tx_desc = NULL;
403 	struct iser_dto *send_dto = NULL;
404 	unsigned long buf_offset;
405 	unsigned long data_seg_len;
406 	uint32_t itt;
407 	int err = 0;
408 
409 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
410 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
411 		return -EPERM;
412 	}
413 
414 	if (iser_check_xmit(conn, task))
415 		return -ENOBUFS;
416 
417 	itt = (__force uint32_t)hdr->itt;
418 	data_seg_len = ntoh24(hdr->dlength);
419 	buf_offset   = ntohl(hdr->offset);
420 
421 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
422 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
423 
424 	tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
425 	if (tx_desc == NULL) {
426 		iser_err("Failed to alloc desc for post dataout\n");
427 		return -ENOMEM;
428 	}
429 
430 	tx_desc->type = ISCSI_TX_DATAOUT;
431 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
432 
433 	/* build the tx desc regd header and add it to the tx desc dto */
434 	send_dto = &tx_desc->dto;
435 	send_dto->task = iser_task;
436 	iser_create_send_desc(iser_conn, tx_desc);
437 
438 	iser_reg_single(iser_conn->ib_conn->device,
439 			send_dto->regd[0], DMA_TO_DEVICE);
440 
441 	/* all data was registered for RDMA, we can use the lkey */
442 	iser_dto_add_regd_buff(send_dto,
443 			       &iser_task->rdma_regd[ISER_DIR_OUT],
444 			       buf_offset,
445 			       data_seg_len);
446 
447 	if (buf_offset + data_seg_len > iser_task->data[ISER_DIR_OUT].data_len) {
448 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
449 			 "inconsistent with total len:%ld, itt:%d\n",
450 			 buf_offset, data_seg_len,
451 			 iser_task->data[ISER_DIR_OUT].data_len, itt);
452 		err = -EINVAL;
453 		goto send_data_out_error;
454 	}
455 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
456 		 itt, buf_offset, data_seg_len);
457 
458 
459 	err = iser_post_send(tx_desc);
460 	if (!err)
461 		return 0;
462 
463 send_data_out_error:
464 	iser_dto_buffs_release(send_dto);
465 	kmem_cache_free(ig.desc_cache, tx_desc);
466 	iser_err("conn %p failed err %d\n",conn, err);
467 	return err;
468 }
469 
470 int iser_send_control(struct iscsi_conn *conn,
471 		      struct iscsi_task *task)
472 {
473 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
474 	struct iscsi_iser_task *iser_task = task->dd_data;
475 	struct iser_desc *mdesc = &iser_task->desc;
476 	struct iser_dto *send_dto = NULL;
477 	unsigned long data_seg_len;
478 	int err = 0;
479 	struct iser_regd_buf *regd_buf;
480 	struct iser_device *device;
481 
482 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
483 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
484 		return -EPERM;
485 	}
486 
487 	if (iser_check_xmit(conn, task))
488 		return -ENOBUFS;
489 
490 	/* build the tx desc regd header and add it to the tx desc dto */
491 	mdesc->type = ISCSI_TX_CONTROL;
492 	send_dto = &mdesc->dto;
493 	send_dto->task = NULL;
494 	iser_create_send_desc(iser_conn, mdesc);
495 
496 	device = iser_conn->ib_conn->device;
497 
498 	iser_reg_single(device, send_dto->regd[0], DMA_TO_DEVICE);
499 
500 	data_seg_len = ntoh24(task->hdr->dlength);
501 
502 	if (data_seg_len > 0) {
503 		regd_buf = &mdesc->data_regd_buf;
504 		memset(regd_buf, 0, sizeof(struct iser_regd_buf));
505 		regd_buf->device = device;
506 		regd_buf->virt_addr = task->data;
507 		regd_buf->data_size = task->data_count;
508 		iser_reg_single(device, regd_buf,
509 				DMA_TO_DEVICE);
510 		iser_dto_add_regd_buff(send_dto, regd_buf,
511 				       0,
512 				       data_seg_len);
513 	}
514 
515 	if (iser_post_receive_control(conn) != 0) {
516 		iser_err("post_rcv_buff failed!\n");
517 		err = -ENOMEM;
518 		goto send_control_error;
519 	}
520 
521 	err = iser_post_send(mdesc);
522 	if (!err)
523 		return 0;
524 
525 send_control_error:
526 	iser_dto_buffs_release(send_dto);
527 	iser_err("conn %p failed err %d\n",conn, err);
528 	return err;
529 }
530 
531 /**
532  * iser_rcv_dto_completion - recv DTO completion
533  */
534 void iser_rcv_completion(struct iser_desc *rx_desc,
535 			 unsigned long dto_xfer_len)
536 {
537 	struct iser_dto *dto = &rx_desc->dto;
538 	struct iscsi_iser_conn *conn = dto->ib_conn->iser_conn;
539 	struct iscsi_task *task;
540 	struct iscsi_iser_task *iser_task;
541 	struct iscsi_hdr *hdr;
542 	char   *rx_data = NULL;
543 	int     rx_data_len = 0;
544 	unsigned char opcode;
545 
546 	hdr = &rx_desc->iscsi_header;
547 
548 	iser_dbg("op 0x%x itt 0x%x\n", hdr->opcode,hdr->itt);
549 
550 	if (dto_xfer_len > ISER_TOTAL_HEADERS_LEN) { /* we have data */
551 		rx_data_len = dto_xfer_len - ISER_TOTAL_HEADERS_LEN;
552 		rx_data     = dto->regd[1]->virt_addr;
553 		rx_data    += dto->offset[1];
554 	}
555 
556 	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
557 
558 	if (opcode == ISCSI_OP_SCSI_CMD_RSP) {
559 		spin_lock(&conn->iscsi_conn->session->lock);
560 		task = iscsi_itt_to_ctask(conn->iscsi_conn, hdr->itt);
561 		if (task)
562 			__iscsi_get_task(task);
563 		spin_unlock(&conn->iscsi_conn->session->lock);
564 
565 		if (!task)
566 			iser_err("itt can't be matched to task!!! "
567 				 "conn %p opcode %d itt %d\n",
568 				 conn->iscsi_conn, opcode, hdr->itt);
569 		else {
570 			iser_task = task->dd_data;
571 			iser_dbg("itt %d task %p\n",hdr->itt, task);
572 			iser_task->status = ISER_TASK_STATUS_COMPLETED;
573 			iser_task_rdma_finalize(iser_task);
574 			iscsi_put_task(task);
575 		}
576 	}
577 	iser_dto_buffs_release(dto);
578 
579 	iscsi_iser_recv(conn->iscsi_conn, hdr, rx_data, rx_data_len);
580 
581 	kfree(rx_desc->data);
582 	kmem_cache_free(ig.desc_cache, rx_desc);
583 
584 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
585 	 * task eliminates the need to worry on tasks which are completed in   *
586 	 * parallel to the execution of iser_conn_term. So the code that waits *
587 	 * for the posted rx bufs refcount to become zero handles everything   */
588 	atomic_dec(&conn->ib_conn->post_recv_buf_count);
589 }
590 
591 void iser_snd_completion(struct iser_desc *tx_desc)
592 {
593 	struct iser_dto        *dto = &tx_desc->dto;
594 	struct iser_conn       *ib_conn = dto->ib_conn;
595 	struct iscsi_iser_conn *iser_conn = ib_conn->iser_conn;
596 	struct iscsi_conn      *conn = iser_conn->iscsi_conn;
597 	struct iscsi_task *task;
598 	int resume_tx = 0;
599 
600 	iser_dbg("Initiator, Data sent dto=0x%p\n", dto);
601 
602 	iser_dto_buffs_release(dto);
603 
604 	if (tx_desc->type == ISCSI_TX_DATAOUT)
605 		kmem_cache_free(ig.desc_cache, tx_desc);
606 
607 	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
608 	    ISER_QP_MAX_REQ_DTOS)
609 		resume_tx = 1;
610 
611 	atomic_dec(&ib_conn->post_send_buf_count);
612 
613 	if (resume_tx) {
614 		iser_dbg("%ld resuming tx\n",jiffies);
615 		scsi_queue_work(conn->session->host, &conn->xmitwork);
616 	}
617 
618 	if (tx_desc->type == ISCSI_TX_CONTROL) {
619 		/* this arithmetic is legal by libiscsi dd_data allocation */
620 		task = (void *) ((long)(void *)tx_desc -
621 				  sizeof(struct iscsi_task));
622 		if (task->hdr->itt == RESERVED_ITT)
623 			iscsi_put_task(task);
624 	}
625 }
626 
627 void iser_task_rdma_init(struct iscsi_iser_task *iser_task)
628 
629 {
630 	iser_task->status = ISER_TASK_STATUS_INIT;
631 
632 	iser_task->dir[ISER_DIR_IN] = 0;
633 	iser_task->dir[ISER_DIR_OUT] = 0;
634 
635 	iser_task->data[ISER_DIR_IN].data_len  = 0;
636 	iser_task->data[ISER_DIR_OUT].data_len = 0;
637 
638 	memset(&iser_task->rdma_regd[ISER_DIR_IN], 0,
639 	       sizeof(struct iser_regd_buf));
640 	memset(&iser_task->rdma_regd[ISER_DIR_OUT], 0,
641 	       sizeof(struct iser_regd_buf));
642 }
643 
644 void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
645 {
646 	int deferred;
647 	int is_rdma_aligned = 1;
648 	struct iser_regd_buf *regd;
649 
650 	/* if we were reading, copy back to unaligned sglist,
651 	 * anyway dma_unmap and free the copy
652 	 */
653 	if (iser_task->data_copy[ISER_DIR_IN].copy_buf != NULL) {
654 		is_rdma_aligned = 0;
655 		iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_IN);
656 	}
657 	if (iser_task->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
658 		is_rdma_aligned = 0;
659 		iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_OUT);
660 	}
661 
662 	if (iser_task->dir[ISER_DIR_IN]) {
663 		regd = &iser_task->rdma_regd[ISER_DIR_IN];
664 		deferred = iser_regd_buff_release(regd);
665 		if (deferred) {
666 			iser_err("%d references remain for BUF-IN rdma reg\n",
667 				 atomic_read(&regd->ref_count));
668 		}
669 	}
670 
671 	if (iser_task->dir[ISER_DIR_OUT]) {
672 		regd = &iser_task->rdma_regd[ISER_DIR_OUT];
673 		deferred = iser_regd_buff_release(regd);
674 		if (deferred) {
675 			iser_err("%d references remain for BUF-OUT rdma reg\n",
676 				 atomic_read(&regd->ref_count));
677 		}
678 	}
679 
680        /* if the data was unaligned, it was already unmapped and then copied */
681        if (is_rdma_aligned)
682 		iser_dma_unmap_task_data(iser_task);
683 }
684 
685 void iser_dto_buffs_release(struct iser_dto *dto)
686 {
687 	int i;
688 
689 	for (i = 0; i < dto->regd_vector_len; i++)
690 		iser_regd_buff_release(dto->regd[i]);
691 }
692 
693